[From Rick Marken (2014.07.14.0830)]
Martin Taylor (2014.07.13.00.16)
RM: Very close. What you are describing is a "stability" measure of QoC, which is the ratio of observed to expected variance of a controlled variable. The observed variance is, as you say, a measure of variation of the controlled variable: observed var(cv) = var(cv). The expected variance of the cv is...var (o) + var (d).
MT: True, but since in the absence of control, var(o) = 0, cv = d.
RM: I think you must know that this is not the case. But if not, you can demonstrate to yourself that it's not true using, once again, the "Control of Size" demo (<http://www.mindreadings.com/ControlDemo/Size.html>http://www.mindreadings.com/ControlDemo/Size.html). Suppose that, in this demo, you control area; in that case perimeter is not controlled but var (o) is not zero because the output is being varied to control area. But even though var(o) is not zero, the stability measure for perimeter will be less than that for area because the variance of the perimeter will be approximately equal to the sum of the variances of output and disturbance.
MT: "Intrinsic controlled variable" sounds like a contradiction in terms. The intrinsic variables are outside the perceptual control hierarchy, and are influenced by the side-effects of control. When they depart from their genetically determined reference values, they alter the perceptual control hierarchy so that the side effects of whatever perceptions we happen to be controlling (eventually, but we hope soon enough) bring them back. That is indeed "control", but it is so different from the control in the perceptual control hierarchy that I think it confusing to use the same word. The control loop diagram would have an output function that varied its gain all over the lot, even changing sign on occasion.
RM: It's called "E. coli reorganization, but that is certainly a control process. So I don't see any reason not to say that intrinsic variables are controlled. It's the kind of controlling that you when you control the "dot" in my "Selection of consequences" demo (<http://www.mindreadings.com/ControlDemo/Select.html>http://www.mindreadings.com/ControlDemo/Select.html). You are controlling the movement of the dot even though the results of your outputs are random. This control is implemented by a process (random variation and selective retention) that is, indeed, somewhat different than the control process that is assumed to be used by the perceptual control hierarchy; so it does merit a different name: E. coli reorganization. But the result in both cases is control; keeping a variable in a predetermined state, protected from disturbance. Actually, the resistance to disturbance aspect of "E. coli reorganization" is demonstrated in Marken, R. S. and Powers, W. T. (1989) Random-Walk Chemotaxis: Trial-And-Error as a Control Process. Behavioral Neuroscience, 103, 1348-1355, which is reprinted in my first collection of papers, "Mind Readings".
Which reminds me. All those of you who are interested in the scientific psychology aspect of PCT, don't for get to order copies of my new book, "Doing Research on Purpose". And while you're at it, if you don't already have them, get copies of "Mind Readings" and "More Mind Readings". If nothing else it will be good for the economy (especially mine;-).
Best
Rick
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Richard S. Marken PhD
<http://www.mindreadings.com>www.mindreadings.com